The art of the present invention relates to fiberoptic endoscopic probes for vitreoretinal surgery in general and more particularly to an apparatus and method for delivery of both broad spectrum illumination and coherent laser treatment pulses through a common optical fiber. The present invention also provides surgical illumination intensity control by providing an apparatus and method for quickly and easily providing a fiber optic illumination light output intensity reference to ophthalmic surgeons. The present invention also utilizes a unique fiber optic connector ferrule which uniquely indicates to the aforesaid apparatus source whether the fiber is designed, best suited, or desired for illumination or laser transmission light or both. Also integral to the present invention is an optical power meter, preferably for measurement of laser output power emanating from the optical fiber.
Prior art vitreoretinal surgical procedure utilizes discrete and separate optical fibers for the delivery of typically non-coherent light for illumination and coherent laser beam light for surgical treatment of tissues. Although prior art “illuminated laser probes” of various configurations have been developed, they all utilize separate optical fiber or fibers for the non-coherent illumination stream and the coherent laser delivery. The aforesaid fibers are typically arranged side by side inside of a common needle lumen. An embodiment of this prior art technology is found in U.S. Pat. No. 5,323,766, issued to Uram. This prior art technology requires a larger or more than one incision in order to introduce illumination and laser treatment light into the eye or other structure, thereby generating greater trauma to the surgical site.
Prior art devices typically utilize a laser deliver core optical fiber diameter of typically 200 to 300 microns since said diameter provides the surgical laser burn spot size most commonly desired by the surgeon. The aforesaid prior art devices have been unable to provide sufficient surgically useful illumination (non-coherent white light) power through such a small fiber, primarily due to the prior art's inability to focus said non-coherent surgically useful light onto such a small spot size. Moreover, none of the prior art devices have combined the aforesaid surgically useful illumination and laser treatment light and transmitted through a single fiber, especially of the aforesaid small size.
The present art apparatus and method provides coaxial delivery of both broad spectrum illumination and coherent laser treatment pulses through a common optical fiber. In a preferred embodiment, the apparatus first comprises a non-coherent light source (coherent in an alternative embodiment) capable of coupling sufficient illumination light into an optical fiber with a core diameter suitable for vitreoretinal laser treatment light delivery. That is, to provide a volume of light to the surgical site which is sufficient for illumination of the surgical procedure. In a preferred embodiment said core fiber diameter is typically 200 to 300 microns since said diameter provides the surgical laser burn spot size most commonly desired by the surgeon. The aforesaid optical fiber is typically a multi-mode stepped index fiber in a preferred embodiment. Alternative embodiments may vary the type and size of the optical fiber without departing from the scope of the present art.
An object of the present invention is to utilize a light source capable of using 250 micron (or smaller) optical fibers while still providing similar surgically useful lumen output to current 750 micron fiber sources (typically 10–12 lumens). The source output aperture of the present invention in a preferred embodiment is at least 0.5 na (numerical aperture). Alternative embodiments may vary this numerical aperture without departing from the scope of the present invention. The color of the light delivered by the present invention appears white despite the light power output or intensity. Also, the output intensity is capable of reduction without significantly affecting the color, aperture, or homogeneity of the light. The output bandwidth of the aforesaid light is substantially limited to the visible spectrum, that is both UV and IR light are minimized. An option for user selectable Limitations (separate from the UV and IR limitations) in the output spectrum is provided. Apparatus conformance to relevant safety standards is also provided.
Prior art illumination light sources typically require a minimum aggregate optical fiber core area equivalent to a fiber diameter of approximately 500 microns in order to deliver sufficient illuminating light to be considered useful by the surgeon. A fundamental prior art limitation with utilization of smaller light fibers for illumination is the size of the focus spot in the light source itself. In a preferred embodiment, the art of the present invention utilizes a small geometry arc lamp which is capable of focusing to an extremely small illumination spot size due to its extremely small plasma ball. This focusing attribute allows for efficient coupling of illumination light into an optical fiber of 100 to 300 micron core diameter which is typically utilized for laser treatment light delivery. Utilization of the aforesaid preferred embodiment allows for up to 40 milliwatts of illumination light to be delivered by a fiber previously considered too small to be an efficient illumination light source.
The aforesaid present art light source includes an input aperture or connector for the attachment of a laser coupling fiber. The aforesaid aperture attachment is somewhat similar to the method by which a treatment laser is attached with an ophthalmic slit lamp. That is, via a fiber optic pigtail typically equipped with a mechanical output connector such as an exi sma. In the preferred embodiment, dichroic optics and/or other optical path design techniques are used to coaxially couple a treatment laser beam into the illumination optical path, and into an endoscopic probe optical fiber. That is, with the aforesaid coupling arrangement (using a single fiber), the present art apparatus and method allows a unique single and smaller optical fiber to be utilized for both illumination and laser treatment purposes. The art of the present invention further provides a new generation of vitreo-retinal endoscopic instrumentation which utilizes the prior art space occupied by larger illumination fibers and is also capable of providing such in a smaller cross-sectional fiber bundle.
The present art accepts laser light from various surgical laser sources, mixes said laser light with illumination light, and launches both down a single fiber. Laser output aperture is minimized and the laser light is not substantially affected by the illumination dimming or other spectral output limiting. An aiming beam is visible within the illumination output pattern. Unique to the present part is a shadow appearance in the output light cone which indicates the location of laser treatment upon activation of a laser light source. Power losses through the system are also minimized. As aforesaid, the laser mixing method does not significantly affect illumination when not in use (i.e. color, aperture, or homogeneity).
Another unique feature of the present art invention is the ability to change the angular light output from an endoscopic probe coupled with the aforesaid coaxial optical fiber by actively controlling the focus characteristics of the light source. That is, prior art light sources have a fixed numerical aperture focus configuration which is typically designed to fill the full acceptance cone of the mating optical illumination fiber. The present art invention further comprises and utilizes surgeon controlled condensing optics to provide a variable focused light output from the endoscopic probe and efficient coupling into different fiber types. This is especially useful for coupling with optical fibers having different numerical aperture requirements.
Ophthalmic surgical illumination devices for use with optical fibers are found in the prior art and have been manufactured by numerous companies for years. One of many such devices is described in U.S. Pat. No. 4,757,426 issued to Scheller, et al. on Jul. 12, 1988, Entitled “Illumination System for Fiber Optic Lighting Instruments”. One of the most widely used illumination devices is the “Millennium” which is manufactured by Bausch and Lomb®. Other manufacturers are Alcon® with the “Accurus” and Grieshaber® with the “GLS150”. Due to the prevalence of the aforesaid within the marketplace, it is desirable for new and high intensity illumination devices, such as the present art device, to provide an intensity reference indication to ophthalmic surgeons which allows them to reliably duplicate or mimic the illumination intensity of one or more of the aforesaid prior art devices. This is especially true since retinal photic injury is a possible complication of the need to use bright light to clearly visualize ocular structures during delicate ophthalmic surgical procedures. The present art invention further represents a novel apparatus and method for providing the ophthalmic surgeon with graphical photoxicity risk information in a clear and easy to understand manner. In a preferred embodiment, it is comprised of an inexpensive card that is removably attached to the control panel of a surgical light source in order to show the relationship between the output intensity of the light source and the likelihood of photic injury.
Further included with the present art apparatus is an integral optical power meter which is in a preferred embodiment, capable of measuring the laser power output emanating from the fiber optic. Alternative embodiments of said laser power meter also measure the illumination power intensity.
Accordingly, it is an object of the present invention to provide a coaxial illuminated laser endoscopic probe and active numerical aperture control apparatus and method of use which is capable of transmitting both illumination (non-coherent) and laser (coherent) treatment light through a single optical fiber of sufficiently small diameter that said fiber may be used for laser treatment, especially in eye surgical or ophthalmic applications.
Another object of the present invention is to provide a coaxial illuminated laser endoscopic probe and active numerical aperture control apparatus and method of use which provides both a surgically useful illumination (non-coherent) output and a combined laser (coherent) output.
Another object of the present invention is to provide a coaxial illuminated laser endoscopic probe and active numerical aperture control apparatus and method of use with an illumination intensity control which is usable by the surgeon to control illumination intensity without affecting laser output power or laser beam spot size characteristics or illumination spectral content.
A further object of the present invention is to provide a coaxial illuminated laser endoscopic probe and active numerical aperture control apparatus and method of use which connects with conventional laser light sources.
A further object of the present invention is to provide a coaxial illuminated laser endoscopic probe and active numerical aperture control apparatus and method of use which provides a shadow or aiming hole within the illumination light cone projection where the laser treatment is placed.
A still further object of the present invention is to provide a coaxial illuminated laser endoscopic probe and active numerical aperture control apparatus and method of use which provides an intensity reference indication to ophthalmic surgeons which allows them to reliably duplicate or mimic the illumination intensity of one or more prior art devices or allows them to understand and minimize phototoxicity risks relating to the illumination output.
A still further object of the present invention is to provide a coaxial illuminated laser endoscopic probe and active numerical aperture control apparatus and method of use which provides a unique ferrule or connector for optical fiber connection which uniquely indicates to the aforesaid apparatus source whether the optical fiber is designed, best suited, or desired for illumination or laser transmission light or both.
A yet further object of the present invention is to provide a coaxial illuminated laser endoscopic probe and active numerical aperture control apparatus and method of use which minimizes trauma to the patient and surgical site.
A yet further object of the present invention is to provide a coaxial illuminated laser endoscopic probe and active numerical aperture control apparatus and method of use which has an integral power meter for measurement of laser output power.